In the case where a CMOS image sensor and a DRAM for temporarily storing image data are packaged on one chip, when a stack type capacitor is used for DRAM cell, a bulk interlayer film from a substrate to a lowermost wiring formed in the upper layer on the stack type capacitor is formed too thick, the entire chip also is accordingly formed too thick. Therefore, if a microlens formed on the surface of the chip is not configured satisfactorily thin, focal length is hardly ensured in accordance with the thickness of the chip. As a result, the light is focused at a point before the substrate.
If sufficient light is not converged to a photodiode, the CMOS image sensor reduces the sensitivity. As shown in FIG. 65, when the inter-layer film is too thick, the light is hardly converged on the surface of the substrate through a microlens. Particularly, when the pixel size is reduced, the above tendency appears considerably.
The present invention has been proposed in view of the above problem. An object of the invention is to provide a semiconductor device capable of preventing the sensitivity from decreasing due to the light irradiated through a microlens being focused at a point in front of a pixel, a manufacturing process thereof and an imaging device.